Programmable Controller Signal Address Overlap Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Programmable controllers face challenges in preventing duplicate writing to signal addresses, leading to malfunctions, especially in configurations where multiple ladder programs share a signal address space, and in multisystem configurations where direct communication between programs is restricted, requiring additional design costs and memory usage.

Innovation Solution

Embedding information about signal address regions into executable ladder programs as available address setting tables, allowing the programmable controller to check for overlaps before execution, preventing duplicate writing and ensuring safe operation without overloading the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple ladder programs share a signal address space, then productivity is improved through parallel execution, but reliability deteriorates due to duplicate writing causing malfunctions

Engineering Contradiction:

Improveparallel execution of ladder programsVSAvoidmalfunction prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by checking for address overlaps between multiple ladder programs before they are executed. The control device analyzes the signal addresses that each ladder program intends to write to, and detects potential conflicts in advance. This prevents duplicate writing malfunctions before they occur, allowing multiple programs to run in parallel safely without compromising reliability.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If an independent signal address space is provided for each ladder program, then reliability is improved by preventing duplicate writing, but device complexity increases and communication between programs is restricted

Engineering Contradiction:

Improveduplicate writing preventionVSAvoidsignal address space configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the benefits of independent address spaces with shared address space functionality. Instead of providing completely separate address spaces for each ladder program, the control device allows programs to share a common signal address space while implementing a checking mechanism that prevents duplicate writing. This combines the simplicity of shared addressing with the safety of independent addressing, reducing device complexity while maintaining reliability.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If a shared signal address space is prepared to allow ladder programs to work in cooperation, then adaptability is improved, but device complexity increases and duplicate writing prevention mechanisms are needed

Engineering Contradiction:

Improvecooperation between ladder programsVSAvoidaddress space management

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing address overlap checking before ladder programs execute. The control device analyzes which signal addresses each program will write to, detects potential conflicts in advance, and prevents duplicate writing before it occurs. This enables adaptable cooperation between programs in a shared address space without requiring complex runtime management mechanisms.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If ladder program execution system performs comprehensive address checking, then reliability is improved by detecting duplicate writing, but productivity deteriorates due to heavy system load

Engineering Contradiction:

Improveduplicate writing detectionVSAvoidsystem load

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent performs address overlap checking as a preliminary action before ladder program execution, rather than continuously during execution. By analyzing and detecting potential address conflicts in advance, the system ensures reliability through comprehensive checking while minimizing productivity impact, as the checking overhead occurs once before runtime rather than continuously during program execution.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10656611B2Programmable controller

Publication Date: 2020.05.19 FANUC LTD

AI summary

A programmable controller capable of checking accessible signal addresses for each of ladder programs is provided. The programmable controller includes signal address setting extraction means for extracting an available address setting table from each of the ladder programs; a signal address overlap determination section for determining whether there is an overlap between the respective ranges of signal addresses used as signal write destinations by the ladder programs, based on the available address setting tables extracted by the signal address setting extraction means; and a ladder program execution section for executing the plurality of ladder programs if the signal address overlap determination section determines that there is no overlap between the respective ranges of signal addresses used as signal write destinations by the ladder programs.